Answer: 3.49 s
Explanation:
We can solve this problem with the following equation of motion:
(1)
Where:
is the final height of the ball
is the initial height of the ball
is the initial velocity (the ball was dropped)
is the acceleratio due gravity
is the time
Isolating
:
(2)
(3)
Finally we find the time the ball is in the air:
(4)
A small 20-kg canoe is floating downriver at a speed of 2 m/s. 40 J is the canoe’s kinetic energy.
Answer: Option A
<u>Explanation:</u>
The given canoe has the mass and is being given to move at a speed. Therefore the kinetic energy of the canoe can be calculated using the following method,
Given that mass of the canoe = 20 kg and its speed =1 m/s
As we know that the Kinetic energy has the formula,

Therefore, substituting the value into the equation, we get,
= 40 J
The answer is (a) because movement is acceleration
Action and reaction are the rocket fuel going backwards and the rocket going forward. 3
f=ma 2
the rocket was at rest, 1, until there was a resultant external force 1 at which point 2 came in, with 3 alongside